Wow! What an awesome list! My favorite is the stock photography because I love photography. I have had some success there, particularly with one photo I make some decent income from. I think the key with stock photography is finding a shot that is high demand. Then, find a new unique way to frame that shot. This is the reason my St. Louis Arch photo is a top 10 on both ShutterStock and iStockPhoto. Thanks for the awesome ideas above!
I have already come up with 50 ways that a management company can screw you for profit without you ever knowing(or not finding out for awhile). Did you have an inspection before you made an offer on the property? Do you have a picture of the property you bought? How do you know if that picture shows the house you actually own? or if it even hows the ‘current’ state of the house you own?

Passive income differs from active income which is defined as any earned income including all the taxable income and wages the earner get from working. Linear active income refers to one constantly needed to stay active to maintain the stream of income, and once an individual chooses to stop working the income will also stop, examples of active income include wages, self-employment income, material participation in an s corp, or a partnership.[4] portfolio income is derived from investments and includes capital gains, interest, dividends, and royalties.[5]

When I purchase an existing online business, I look for cash flow over the past year and where the money comes from. I want the sources to be more passive so that it does not take a lot of my time. Also, typically I will make an offer that is 18 – 24 months of profit so that I know that I will get my money back within the next two years. I hope that helps!
If you have specialized knowledge in a certain topic, you can put together an online course to teach others. For example, if you have experience in real estate investing, you can create an online course “Real Estate Investing 101”. The benefit of an online course is that once you create the course material, you can sell it to as many people as you want.
SSME is the marketing arm of Wealth Creations Network. Ms Brantley began developing this amazing concept about three years ago. It has evolved and come to be what it is today through personal trials and experiences. Losing her $80,000 per year job catapulted Selina into aggressively moving forward with a solution to today's economic downturn. Ms. Brantley has personally spent thousands of dollars on web building education, business building coaches, financial mentors and advisors, search engine optimization techniques and strategic marketing information.
Another way to generate passive income is to invest and be a silent partner in a business. This is very risky, but with risk comes the potential for high returns. For example, several years ago both Lyft and Uber were looking for private investors to invest in their companies. Today, they are worth billions - but you as an investor would only reap that benefit if they go public via an IPO, or get acquired. So, it's risky.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.